Can't turn off previous output. (X/O button not saving it's state)

Open up a command block. Click X. Then Done. Re-Open command block and the previous output is still there and button is O

Also is there a /blockdata command to update the "Previous Output" flag? Save clicking in a few hundred blocks to turn it off.

Tested this with (client) 1.8.3/1.8.7 (server 1.8.7)